Uterine malignant mixed Müllerian tumor camouflaging as pelvic sarcoma

Malignant mixed Müllerian tumors (MMMTs) of the uterus are rare, aggressive tumors that present at an advanced stage and are associated with poor prognosis. They arise as a result of divergent carcinomatous and mesenchymal differentiation of tumor stem cells. Rarely one of the components may predominate contributing to diagnostic confusion. We present a rare case of uterine MMMT arising in endometrial adenocarcinoma, camouflaging as pelvic sarcoma with a major sarcomatous component. This case report highlights the importance of thorough tissue sampling and the role of immunohistochemistry (IHC) in arriving at an accurate diagnosis. This case also demonstrates the conversion theory of histogenesis of MMMTs.